I guess I assumed that it was due to a lack of a big body guy who is good at running slants. But maybe it's just not a big part of the scheme? It does seem like the system doesn't really have a lot of options for countering the blitz and that running more quick slants would help. But, maybe the don't have the personnel to run it effectively?
I noticed that when Rattler was in at QB the offense had no answer for the blitz. I guess I assumed he just wasn't getting the ball out fast enough or they were locking down Kamara on the check down, but thinking back I don't think they they gave him a lot of quick options like slants so maybe it's more of a fault with the scheme than Rattler or Carr for that matter?